1. Field of the Invention
This invention relates to an optical information reading apparatus of a portable or hand-held type.
2. Description of the Related Art
Optical information reading apparatuses of a portable type include bar-code readers and bar-code handy terminals. A prior-art bar-code handy terminal has an internal RAM. The bar-code handy terminal reads out data from a bar code, and stores the read-out data into the RAM. The bar-code handy terminal transmits the data from the RAM to a host apparatus by radio communication or optical communication. During operation of the bar-code handy terminal, data is frequently written into and read out from the RAM. The reason why the RAM is used in the bar-code handy terminal is that the RAM is suited for a memory frequently accessed. The RAM is enabled to continuously hold data therein by continuous feed of electric power thereto. The continuous power feed to the RAM causes an increased rate of power consumed by the bar-code handy terminal.
A prior-art advanced bar-code reader includes a nonvolatile memory in addition to a RAM. The nonvolatile memory is a flash memory. In the advanced bar-code reader, when a power supply switch is changed to an off position, data is transferred from the RAM to the flash memory and is saved therein and then power feed to the RAM is cut off. Data can be written into the flash memory a number of times, the upper limit of which is relatively low. Accordingly, the flash memory has a problem in its life.
Japanese published unexamined patent application 6-259338 discloses a system including a main memory, a nonvolatile memory, a backup battery, and a timer. When main power supply is cut off, the backup battery is used instead thereof. Then, the main memory continues to be fed with power from the backup battery so that the main memory continuously holds data therein. When a predetermined time given by the timer has elapsed from the moment of the cutoff of the main power supply, the data is transferred from the main memory to the nonvolatile memory and is saved therein. According to the system of Japanese patent application 6-259338, it is possible to reduce the number of times data is written into the nonvolatile memory. In the system of Japanese patent application 6-259338, power from the backup battery is used for the transfer of data from the main memory to the nonvolatile memory and also the activation of the nonvolatile memory. Thus, the backup battery tends to be great in capacity and size.
It is an object of this invention to provide a small-sized optical information reading apparatus of a portable or hand-held type.
A first aspect of this invention provides an optical information reading apparatus of a portable type. The optical information reading apparatus comprises reading means for reading optical information and converting the optical information into electric information; volatile memory means for storing the electric information generated by the reading means; nonvolatile memory means; a first power supply for feeding electric power to at least the reading means and the volatile memory means; a second power supply; changing means for replacing the first power supply by the second power supply and enabling the second power supply to feed electric power to at least the volatile memory means instead of the first power supply in cases where electric power feed by the first power supply is required to be cut off; and writing means for transferring the electric information from the volatile memory means to the nonvolatile memory means, and writing the electric information into the nonvolatile memory means when a predetermined time has elapsed since a moment at which the electric power feed by the first power supply is required to be cut off; wherein the changing means replaces the second power supply by the first power supply and enables the first power supply to feed electric power to at least the volatile memory means instead of the second power supply before the writing means transfers the electric information from the volatile memory means to the nonvolatile memory means and writes the electric information into the nonvolatile memory means, and wherein the first power supply feeds electric power to the writing means and the nonvolatile memory means.
A second aspect of this invention is based on the first aspect thereof, and provides an optical information reading apparatus further comprising means for inhibiting electric power feed by the second power supply after the writing means transfers the electric information from the volatile memory means to the nonvolatile memory means and writes the electric information into the nonvolatile memory means.
A third aspect of this invention is based on the first aspect thereof, and provides an optical information reading apparatus further comprising means for transferring the electric information from the nonvolatile memory means to the volatile memory means in cases where electric power feed by the first power supply is restarted after the writing means transfers the electric information from the volatile memory means to the nonvolatile memory means and writes the electric information into the nonvolatile memory means.
A fourth aspect of this invention provides an optical information reading apparatus of a portable type. The optical information reading apparatus comprises a volatile memory; a nonvolatile memory; a main power supply; an auxiliary power supply; first means for enabling the main power supply to activate the volatile memory; second means for storing data into the volatile memory; third means for enabling the auxiliary power supply to activate the volatile memory instead of the main power supply when activation of the volatile memory by the main power supply is required to be suspended; fourth means for enabling the main power supply to activate the volatile memory instead of the auxiliary power supply when a predetermined time has elapsed since a moment at which the third means enables the auxiliary power supply to activate the volatile memory instead of the main power supply; and fifth means for transferring the data from the volatile memory to the nonvolatile memory after the fourth means enables the main power supply to activate the volatile memory instead of the auxiliary power supply.